<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>选择器</title>
    <style>
        .red{
            color:#900;
        }
        .size30{
            font-size: 90px;
        }

        #div1{
            width: 100px;
            height: 100px;
            background-color: aqua;
        }

        *{
            margin:1px;
            padding: 0px;
        }

        div span{
            color: blueviolet;
        }

        div > span{
            font-size: 50px;
        }

        /*并集，隔开
        */
        ul,li,ol,p{
            size: 100px;
            margin-left: 100px;
            color: #900;
        }
    </style>
</head>
<body>
    <span class="red size30">red size30</span>
    <br>
    <span class="red">red</span>
    <br>
    <span class="size30">size30</span>
    <div id="div1">niahoshijie</div>
    <div>
        <span>niaho</span>
        <ol>
            <li>
                <span>niahonihao</span>
            </li>
        </ol>
    </div>


    <ul>
        <li>nihao</li>
        <li>shijie</li>
        <li>zhangsan</li>
    </ul>
    <ol>
        <li>zhangsjan</li>
        <li>lisjhio</li>
        <li>lisjhio</li>
    </ol>
    <p>nihaohaohaohao</p>
    <p>nihaohaohaohao</p>
</body>
</html>